grpc_java_server

grpc with java server

About the project

This is java implementation of the grpc server, It has services defined in resource/proto files based on that client side code will be generated

Steps to build the project

• clone the project and import as maven project in eclipse or intelij mvn clean install
• start the server by runing the GRPCServer in server package
• right click on pom.xml and then run the default profile, that will generate the stubs if not already generated
• Use the rpc Boom to call the services, You have to import the protobuff files from the src/main/resources
• You can use the grpc_java_client to call the services buy passing the protobuff files.

Defining a proto file

syntax = "proto3";

option java_package = "patientProto";

service PatientService{
	rpc getPatient(PatientRequest) returns (PatientResponse);
	rpc addPatient(Patient) returns (AddDeletePatientResponse);
	rpc deletePatient(Patient) returns (AddDeletePatientResponse);
	rpc getAllPatients(EmptyResponse) returns (PatientResponse);
}

message PatientRequest{
	int32 identifier = 1;
	string name = 2;
}


message PatientResponse{
 repeated Patient patient = 1;

}
enum Gender{
	MALE = 0;
	FEMALE = 1;
}
enum MaritalStatus{
	MARRIED = 0;
	UNMERRIED = 1;
}

message Patient{
	int32 identifier = 1;
	string name = 2;
	Gender gender = 3;
	bool active = 4;
	string address = 5;
	MaritalStatus maritalStatus = 6;
    string link = 7;
    repeated string language = 8;
    repeated Provider careProvider = 9;
    string managingOrganization = 10;
    repeated Contact guardian = 11;
}

message Provider{
	string name = 1;
	int32 identifier = 2;
	int32 tin = 3;

}

message Contact{
	string name = 1;
	string relationWithPatient = 2;
	string cotactDetails = 3;
}

message AddDeletePatientResponse{
	string successMessage = 1;
	string errorMessage = 2;
	int32 statusCode = 3;

}

message EmptyResponse{

}

Implementing a Service

• First you service class should extends PatientServiceImplBase which you should get when you would have build the project for proto file
• You should implement the unimplemented methods in the service and provide the custom implementation of that

public class PatientService extends PatientServiceImplBase {
	
	
	private static Map<Integer,Patient> map = new HashMap<>();
	
	@Override
	public void getPatient(PatientRequest request,
	       StreamObserver<PatientServiceOuterClass.PatientResponse> responseObserver ) {
		PatientResponse.Builder response  = PatientResponse.newBuilder();
		Patient patient = map.get(request.getIdentifier());
		if(patient!=null) {
			response.addPatient(0, patient);
		}
		responseObserver.onNext(response.build());
		responseObserver.onCompleted();
		
	}
	
	@Override
	public void addPatient(Patient request,
	        StreamObserver<AddDeletePatientResponse> responseObserver) {
		   map.put(request.getIdentifier(), request);
		   System.out.println("Got the call from client inside addPatient method with input: "+request);
		   System.out.println("map size is : "+map.size());
		   System.out.println("map is : "+map.toString());
		   AddDeletePatientResponse.Builder  response = AddDeletePatientResponse.newBuilder();
		   response.setStatusCode(200);
		   response.setSuccessMessage("Successfully added the patient with name : "+request.getName()+" and id : "+request.getIdentifier());
		   response.setErrorMessage("");
		   responseObserver.onNext(response.build());
		   responseObserver.onCompleted();
		   
	}
 }

Define a server in GRPC

Server server = ServerBuilder.forPort(9094)
				.addService(new PatientService())
				.build();
		server.start();
		server.awaitTermination();

Now you can start the server and call it from the client.

Contributing

Please raise an issue if you find anything which is not working or want unimplemented functionality.

License

MIT